NASA Cassini Discovers Plastic on Saturn's Alien Moon, Titan

Plastic is used in thousands of household items. But propylene, the chemical used to make food-storage containers, car bumpers and other products, isn't only found on Earth. NASA's Cassini spacecraft has also detected the material on Saturn's moon, Titan.

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"This chemical is all around us in everyday life, strung together in long chains to form a plastic called polypropylene," said Conor Nixon, lead author of the new paper, in a news release. "That plastic container at the grocery store with the recycling code 5 on the bottom--that's polypropylene."

Cassini has been collecting information about Titan for months. In this case, the spacecraft used its Composite Infrared Spectrometer (CIRS). This instrument measured the infrared light, or heat radiation, emitted from Saturn and its moons in much the same way our hands feel the warmth of a fire. Cassini isolated the same signal at various altitudes within the lower atmosphere and identified propylene.

On Titan, hydrocarbons form after sunlight breaks apart methane, the second-most plentiful gas in the moon's atmosphere. These newly freed fragments can link up to form chains with two, three or more carbons. The family of chemicals with two carbons includes the flammable gas ethane. Propane, a common fuel for stoves, belongs to the three-carbon family. Yet detecting propylene was more difficult. In fact, the Voyager I spacecraft, which made the first-ever close flyby of this moon in 1980, did not detect the chemical.

"This measurement was very difficult to make because propylene's weak signature is crowded by related chemicals with much stronger signals," said Michael Flasar, one of the researchers, in a news release. "This success boosts our confidence that we will find still more chemicals long hidden in Titan's atmosphere."

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The findings are important for better understanding the moon's atmosphere. In addition, it helps further research into the chemical zoo that makes up Titan. The study also shows the importance of using new and better instruments in order to detect these chemicals.